JAVA map遍历 Map集合的2种循环方式。一种是通过map.entrySet()。另一种是map.keySet()。所有的集合都可以通过迭代器Iterator，进行遍历。package learn.javase; import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.Map.Entry; import java.util.Set; /** * 重要 * 遍历map的两种方式map.entrySet() map.keySet() * @author Jole * */ public class MapDemo { public static void main(String[] args) { Map<Integer ,String > map = new HashMap(); map.put(1, "111"); map.put(2, "2222"); //方式一 entrySet() Set<Map.Entry <Integer, String>> sets = map.entrySet(); //获取值1，通过for for(Map.Entry <Integer, String> entry : sets) { System.out.println("ssss:"+entry); System.out.println("key:"+entry.getKey()+"value:"+entry.getValue()); } //获取值2，通过iterator Iterator <Map.Entry <Integer, String>> itt = sets.iterator(); while(itt.hasNext()) { Map.Entry <Integer, String> entrys = itt.next(); System.out.println(entrys.getKey()+"----"+entrys.getValue()); } System.out.println(map.put(3, "222")); //方式二 keySet() Set<Integer> set = map.keySet(); Iterator it = set.iterator(); while(it.hasNext()) { System.out.println("Iterator="+it.next()); System.out.println("key:"+map.get(it.next())); } for(Integer in : set) { System.out.println(in); } } }